(a) Field of the Invention
The present invention relates to a positioning method and system, and more particularly, to a device for collecting infrastructure-related information based on an indoor map and a positioning method and system using the same.
(b) Description of the Related Art
Positioning techniques using a wireless communication infrastructure vary depending on types of intrastructures and a service coverage, and a global navigation satellite system (GNSS), a global positioning System (GPS), a global navigation satellite system (GLONASS), and Galileo in Europe, are currently operating or due to be operated.
The GNSS, which is disposed to serve the global area of the earth, provides high location accuracy within about 10 m or less and availability in flatlands or the suburbs in which a direct line of sight between a satellite unit that transmits a satellite signal and a reception unit that receives the satellite signal is secured, but causes a location error of about 50 m due to a multi-path error in a downtown congested area, i.e., a non-line-of-sight area. In particular, the GNSS has a problem in that the sensitivity of a reception signal is degraded in an indoor area, such that it fails to acquire a signal, so it is not possible to determine a location.
A cellular-based positioning technique is a technique for determining the location of a user by using location information and a measurement signal of a mobile communication base station, which is classified into a Cell-ID, enhanced-observed time difference (E-OTD), advanced-forward link trilateration (AFLT), and the like, depending on the number of base stations from which a terminal can receive signals. Owing to the characteristics of a mobile communication infrastructure having a service range covering a downtown area and most suburban areas, the GNSS has an advantage of allowing determination of a location even in an indoor area as well as in an outdoor area, but its accuracy of positioning varies depending on a disposition density of base stations and it has a relatively low location accuracy of about 100 m to 800 m on average. Therefore, the GNSS does not fit an indoor or outdoor navigation service, or the like, that requires location accuracy of about a few meters.
An assisted-GNSS (A-GNSS) refers to a technique of acquiring auxiliary information of a positioning server in order to improve a minimum reception signal sensitivity of a GNSS receiver installed in a user terminal and shorten time for determining an initial location (i.e., time to first fix). This technique allows fast determining of a location by using the GNSS in a downtown congested area in which a signal strength is weak, but cannot expect to obtain a great effect in an indoor area in which signal strength is very weak.
A wireless local area network (WLAN)-based positioning technique is a typical method for resolving the difficulties of the foregoing indoor positioning, which calculates the location of a terminal by using a reference location of a WLAN access point (AP) and a measurement signal. The WLAN-based positioning technique is divided into a method for acquiring a reference position of an AP, and a method for determining the location of a terminal by using the acquired reference location of the AP and a measurement signal. The method for acquiring the reference location of the AP includes a method for using the location of an AP voluntarily registered by a user through a certain device (e.g., device positioning using a Place Lab radio mark in the wild) and a method for calculating the location of an AP by a limited provider by processing measurement information collected through a planned path by using a dedicated device, and the like.
However, the existing methods for acquiring a reference location of an AP have a problem in that the accuracy of a calculated location of an AP is low, so the provided positioning service is limited. In detail, first, when the location of an AP is calculated by associating GPS coordinates acquired from an outdoor road through a GPS receiver of a certain terminal or a scanner vehicle and AP measurement information, an error increases according to an increase in the distance between a collecting device and the AP, so it is not possible to precisely determine the location of the AP within a few meters. Second, when APs are positioned within a building so transmission signals of the corresponding APs cannot be received or when collecting locations are in an area in which a GPS location reception is not available, it is not possible to determine the locations of the APs. Third, user location information obtained by calculating such AP location information is not suitable to be applied to navigation of a large-scale indoor building (an airport, an exhibition hall, a large-scale mart, an indoor parking lot, etc.) requiring relatively precise indoor positioning and a pedestrian guidance service, such that it is limited in providing a service. In order to solve such problems, a positioning system using a dedicated infrastructure is in use in a limited indoor space. The use of the positioning system ensures obtaining of a location accuracy level of 1 m to 3 m; however, because a dedicated infrastructure must be installed within each indoor building, the installation period is increased and much cost is incurred. Also, because most users are not aware of the locations of APs arbitrarily installed for the purpose of radio communication, they cannot use the APs in determining a location. In addition, it is not possible to install the dedicated infrastructure in a plurality of indoor buildings within a service area, causing a difficulty in providing a wide area service. Moreover, in order to determine the location of a user, the locations of APs must be manually determined for a database through measurement in installing the APs.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.